Sewing machine looper mechanism



.June 20, 1944. i E ,MUECKE 2,351,831

` SEWING MACHINE LooPER MECHANISM y Filed Feb. 25, i945 2 sheets-sheet 1 June 2o, 1944. E. MUECKE l 2,351,831v

SEWING MACHINE LOOPER MECHANISM I Filed Feb'. 23, 1943 2 Sheets-#Sheet 2v f (mb,

.,I. ii Edv Patented June 20, 1944 ENT *orti-cci* SEWING iv'iAcnINli LOOPER MECHANISM Edward Muecke, Linden, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application lebruarif 23, 1943, Serial No. 476,831

This. invention relates to loopcr mechanisms for sewing` machines and particularly to looper mechanisms for sewing machines of the twothread chain-stitch type. Y

The ,present invention has for an object to provide an improved mechanism for moving a looper element in a substantially 'straight path as'it enters the needle loops so that the looper maybe movedclose behind the needles thereby to avoid any possible skipping of the needle loops.

Another object of this invention is Ato provide an extremely compact looper mechanism of the character referred to with actuating means so constructed and arranged as to permit the same to be lubricated freely and to be operated quietly and smoothly at high speeds.

, The-novel and characteristic features of this invention are set forth particularly in the appended claims. The invention itself, however, bol-.hin structure and in operation, as well as additional Vobjects thereof; will be best understood from the following description: x

Fig. 1 is a front elevation, partly in section, of a portionof a sewing machine embodying the present invention. Y

Fig. 2 is a vertical section view taken substantially along line 2 2 of Fig. l.

Fig. v3 lis a top plan View, partly in section, of the `present invention.

'lil-ig.- 4 is a vertical section view taken substan tially along line fl-ll of Fig. l.

'.livig.v 5 is a diagram illustrating the action o f a'crank and link connection. p

Figs. 6 and 'I are diagrams illustrating the l paths of movement of two diiierent looper elements as viewed in top plan. y y

Thev present invention is shown embodied in a sewing machine of the type disclosed in the United States patent to Albert H. DeVoe, No. 1-,1oo,12`4,dated June 16, 1914.

Referring more particularly to the drawings thefinvention is shown as applied to a sewing machine comprising a base li,.ieeding mechansmll, cloth-presser l2 and a needle-bar I3 which latter carries the needles lll. Journaled in bearings l and l carried by the base IB, is 'a inai'nfo'r actuating shaft l'l which is rotated in a manner common to sewing machines.

.The improved looper mechanism comprises one ormore loopers I8 secured by means oi a screw lBuDOn a substantially vertically disposed loopercarrier 20 provided at the lower portion thereof witna horizontally disposed tubular sleeve or support 2l Iwhich is slidably mounted upon a stationary f ulcrum arbor 22. Projecting upwardly from ,the frame lll is a bearing block 23 provided Withfan aperture 24 for the purpose of receiving thefforward portion of the arbor 22 of which therear portion is pointed, as at 25, and mounted within a seat 2B formed in the base I0.` This arbor is 'disposed transversely of the main shaft v* s claims. (01.1.12-200) Hand it; is rigidly secured in position by .means of a set screw 21. f

l. Adjust-ably clamped upon the sleeve .2l -.by means of screws 28 is a split collar 29 from one side of which projects an arm 3c .carrying a ball 3| provided with a steady-pin 32. This ball 3| is received within the socket portion 33 formed onthe lower end of a vertical pitman 3:4 of which the strap portionv 311 surrounds an eccentric 35 fastened upon the shaft Il. Tofthe. lower portion of this pitman 34 there is secured .by means of a screw :it a slotted guide-block 3l which coacts With the pin 32 to steady the pitmanand prevent it from wobbling on the eccentric 3E. Rotation of the shaft l1 will oscillate, through the medium of the eccentric 35, pitman 34,'and arm 30, the looper 2li backend forth about the fulcrum arbor thus to producethe loop-seizing movementsv of the looper I8. -The path of loop-seizing movements lies in a ,direction across the line of seam-formation.

Sidewise or needle-avoiding movementsY are imparted to the looper from an eccentric 38 secured'upon the shaft ll. Embracing the eccenftric 38 'is a strap 39 of a short horizontalpitman Ml carrying crosswise of one end thereof 'ia' pin 4l vwhich is `secured thereto bymeans of 'a `,set screw 42. The opposite end portions of the pin 4l are embraced bythe spaced arms 43 of a hanged bolt 4 `which is threaded into a horizon.- tal guide-rod. This guide-rod lliiis disposed in parallel relation with the arbor 22 andit is slidingly received within an apertured bearing d6 which is secured within the block 23 by means of set screws 4l.

`Clamped between the flanged portion 4,8 ,of the bolt 44 and one end of theguide-rod ll'isA a shouldered collar 49 which is slidingly received within an arcuate slot 50 formed'in the loopercarrier 20. Although vthe collar 49 is Vrigidly clamped between the rod 45 and the flange' .14,8 enough clearance is provided between the collar and the ange to insure that the louper-carrier may slide relative thereto.

Rotation of the eccentric 38- will reciprocate the guide-rod 45 in the directiony of seam forma.- tion and it will thereby impart the sidewise movements vto the looper-carrier 20 `which rwill remain vertically disposed at all times as its sleeve 2l may slide back and forth longitudinally of the arbor 22 simultaneously with the rocking movement of the sleeve. Rotationof the shaft I1 will impart, through the medium of eccentrics 35 and 38 and their accompanying mechanisms, both the loop-seizing and the sidewise movements to the looper element I8.

Thus the sleeve 2l and the guide-rod 45 comprise appair of spaced parallel members which are supported to slide transversely of the mainshaft f1, the looper-carrier 26 being rigidly mounted upon the sleeve 2l and being slidngly connected with the guide-rod 45.

A usual type of looper mechanism, when viewed in top plan view, imparts an elliptical shaped path of movement to its looper, which path has the major axis thereof usually dis-l looper mechanism is employed.- in a sewing'ma-- The applicant realizes that he is not the first to employ an eccentric and short pitman mechanism for imparting the sidewise movements to a looper but he does believe himself to be the rst inventor of the present compact and simple mechanism which permits the eccentric and posed substantially transversely of the direction' of seam formation. Fig. 7 illustrates such'ja chine having a plurality of needles, diiiicultylisfw i experienced for the reason that as the spacing tween the needles and the looper path are also changed. Of course if the distance between the needle and the looper path became very great the looper will be unable to seize the needle loop when the looper passes behind the needle. This condition is illustrated in Fig. 7 which shows that needle I4' by being spaced from needles I4 is consequently shifted away from the looper path 58. Therefore, the use of a looper having an elliptical path of movement, as shown in Fig. '7, limits the spacing between the needles to only the relatively narrow gauges.

The present mechanism obviates the above described diiculty as its looper traverses a path, as viewed in top plan, in the form of a flattened ellipse, the flattened portion of the ellipse representing the loop-seizing portion of the looper movement. This path of movement is illustrated in Fig. 6 and from this figure it may readily be understood that the spacing between the needles I4 may be varied within wide limits without yappreciably affecting the distance between the needles and the path of looper movement. Therefore, the needles of the present machine may be set for wide gauge stitching without the danger of the looper skipping the needle loops. Y

This flattened ellipse is produced by utilizing an eccentric 3B and an extremely short length pitman 40 for imparting the sidewise movements to the looper. Fig. illustrates the 'action of the eccentric 38 and the short pitman 40 by showing the paths of movement of an equivalent mechanism, namely a rotary crank 5l and a link 52 one end of which is confined to straight line movement. Fig. 5 is drawn on a scale subvstantially three times that of the Fig. 4 for the purpose of better illustration. l

As the crank 5I rotates in a clockwise direction from point 53 to point 54 the free end ofthe link 52 moves from point 55 to point 5E and return which movement represents a substantially greater distance than that covered by the free end of the link when it moves from point 55 to point 51 and return as the crank rotates clockwise from point 54 to point 53. 52 was infinitely long the distance B would equal distance A, and as the length of the link 52 becomes shorter relative to crank 5| the difference between distances A and B becomes proportionately greater. employ a rotary eccentric and a relatively short pitman for imparting the sidewise movements to a. looper as the movements derived therefrom, when combined with the back and forth movements of the looper, produce an elliptical path of which one side is flattened. Fig. 6 illustrates by line 5B the top plan view of the path of movement of the present looper element I8. When the eccentric 38 is in a dead center position the pitman 40 is aligned with theguide-rod 45.

If the link Therefore, it is advantageous -to short pitman to be most effectively employed. Fig. 3 well illustrates the compactness of the present looper-actuating unit.

Dueto the fact that the present mechanism has been designed for high-speed operation proy vision has been made for fully lubricating the between the needles is varied,` to meet the divers 1' sewing conditions, the relative distances y be- Ysame. Lubricant is delivered, from a source not ally projecting from the passageway 64 for the purpose of distributing lubricant to the relatively moving surfaces of the arbor 22 and the sleeve 2l.

As illustrated in Figs. l and 3, pipe 59 communicates with the horizontally disposed duct 66 formed in the shaft Il for the purpose of delivering lubricant to the radially disposed ducts 61 which are formed in the shaft I1 and the eccentric 35 thereby to lubricate the surfaces of the eccentric 35 and pitman strap 34. As best shown in Figs. 3 and 4 the duct 66 continues Within the shaft I1 beyond the eccentric 35 to join a radial duct 68 formed in the shaft I1 and the eccentric 38 for the purpose of delivering lubricant to the interengaging surfaces between the eccentric 38 and the pitman strap 39.

Intermittently connected with the radial ducts 61 is a vertical duct B9 located in the pitman 34 and adapted to deliver lubricant to the ball 3l and socket 33. A portion of this lubricant will find its way to the angular shaped duct'lll which leads to interengaging surfaces of the arbor 22 and sleeve 2|. Thus it may be seen that the present device is fully lubricated.

Having thus set forth the nature of vention what I claim herein is:

1. In a sewing machine looper-actuating mechanism'having a main-shaft, an actuating member and an eccentric mounted upon said mainshaft, an arbor disposed transversely of said main-shaft, a looper-carrier slidingly and pivotally mounted upon said arbor, a looper mounted upon said carrier and having a blade confined to parallelism with a fixed plane, and a connection between said actuating member and said looper-carrier for rocking the latter about said arbor; the improvement which comprises the provision of a pitman of which one end is connected directly with said eccentric, the body of said pitman being disposed, when in a dead cen'- ter position in parallelism with said arbor and the other end thereof being connected tosaicl looper-carrier for sliding the same lengthwise of said arbor. 2. In a sewing machine looper-actuating mechanism having a main-shaft, an actuating memberand an eccentric mounted upon said mainshaft, an arbor disposed transversely of said main-shaft, a looper-carrier slidingly and pivotally mounted upon said arbor, a looper mounted the inupon said carrier and having a blade confined to parallelism with a fixed plane, and a connection between said actuating member and said looper-carrier for rocking the latter about said arbor; the improvement which comprises the provision of means sldingly connected with said looper-carrier and conned to straight line movement parallel to said arbor, and a pitman of which one end is connected directly with said eccentric, the body of said pitman being disposed, When in a dead center position, in parallelism with said arbor and the other end thereof being pivotally connected with said means for sliding said looper-carrier lengthwise of said arbor.

3. In a sewing machine looper-actuating mechanism having a main-shaft, an actuating member and an eccentric mounted upon said main-shaft, a support mounted to slide lengthwise of itself in a direction transversely of said main-shaft, a looper-carrier rigidly mounted upon said support, and a connection between said actuating member and said looper-carrier for rocking the latter about the longitudinal axis of said support; the improvement which comprises the provision of a guide member whose longitudinal axis is constantly parallel to that of said support and lies in a plane containing the axis of said main-shaft, said guide member being sldingly connected with said looper-carrier, and a pitman of which one end is connected directly with said eccentric, the body oi said pitman being disposed, when in a dead center position, in alignment with said guide member and the other end thereof being pivotally connected with said guide member for sliding the same end- Wise of itself.

4. A looper-actuating mechanism for sewing machines, comprising, a main-shaft, a pair of eccentrics mounted on said main-shaft, a pair of spaced parallel members supported to slide transversely of said main-shaft, a looper-carrier rigidly mounted upon a rst one of said parallel members, said looper-carrier being sldingly connected with a second one of said parallel members, a pitman embracing one of said eccentrics and being connected with said rst one of said parallel members for rocking the same about its longitudinal axis, and a second pitman embracing the other one of said eccentrics and being connected to said second one of said parallel members for sliding the same lengthwise of itself.

5. In a sewing machine looper-actuating mechanism having a main-shaft, a looper having a loop-seizing blade, a looper-carrier movable in two directions respectively lengthwise and crosswise of said blade and conned against movement in all other directions, a xed supporting member for said looper-carrier arranged transversely of and at one side of said main-shaft, and means actuated by said main-shaft for rocking said looper-carrier about the transverse axis of said fixed supporting member; the improvement which comprises the provision of a guide member whose longitudinal axis is parallel to that oi said supporting member and lies in a plane containing the axis of said main-shaft, satid guide member being sldingly connected with said looper-carrier, and means actuated by said mainshaft and connected with said guide member for shifting said looper-carrier longitudinally of said guide member.

6. In a sewing machine looper-actuating mechanism having a main-shaft, an actuating member and an eccentric mounted upon said mainshait, a support mounted to have rocking movements about and sliding movements lengthwise of an axis disposed transversely and at one side of said main-shaft, a looper-carrier rigidly mounted upon said support, and a connection between said actuating member and said support for rocking the same about the axis of said support for imparting loop-seizing movements to said looper-carrier; the improvement which comprises the provision of a guide-rod whose longitudinal axis is disposed transversely of and ,lies in a plane containing the axis of said mainshait, a collar carried by one end of said guiderod and sldingly embracing said looper-carrier so that the latter may shift transversely of said guide-rod, and a pitman of. which one end is comiected directly with said eccentric, the other end being connected to said collar for shifting said guide-rod endwise of itself, thereby imparting sidewise movements.to said looper-carrier.

7. In a sewing machine looper-actuating mechanism having a main-shaft, a looper having a loop-seizing blade, a looper-carrier movable in two directions respectively lengthwise and crosswise of said blade and confined against movement in all other directions, a xed supporting member for said looper-carrier arranged transversely of and at one side of said main-shaft, and means actuated by said main-shaft for rocking said looper-carried about the transverse axis of said fixed supporting member; the improvement which comprises the provision of a guide-rod whose longitudinal axis is disposed transversely of and lies in a plane containing the axis of said main-shaft, a collar carried by one end of said guide-rod and sldingly embracing said loopercarrier, an eccentric mounted upon said mainshaft, and a pitman of which one end is connected directly with said eccentric, the body of said pitman being disposed, when in a dead center position, in alignment with said guide-rod, the other end thereof being pivotally connected with said collar.

8. A looper-actuating mechanism for sewing machines, comprising, a main-shaft, a pair of eccentrics mounted upon said main-shaft, a pair of spaced parallel members supported to slide transversely of said main-shaft, a rst one of said members having its longitudinal axis lying in the plane containing the axis of the mainshaft, a looper-carrier rigidly mounted upon a second one of said parallel members and having an elongated slot provided therein, a pitman embracing one of said eccentrics and being connected with said second member for rocking the same about its longitudinal axis, a collar rigidly secured upon one end of said rst member, said collar being received within said elongated slot and sldingly embracing the opposite sides of said looper-carrier, and a pitman embracing the other one of said pair of eccentrics and being pivotally connected to said collar, the body of said pitman being disposed, when in a dead center position, in alignment with said second member.

EDWARD MUECKE. 

